import greenfoot.*;  // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)

/**
 * Write a description of class MainMenu here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class MainMenu extends World
{

    /**
     * Constructor for objects of class MainMenu.
     * 
     */
    public MainMenu()
    {    
        super(490, 475, 1); 
        addObject(new ChoseModelButton("单人模式"), getWidth()/2, 100);
        addObject(new ChoseModelButton("双人模式"), getWidth()/2, 200);
        addObject(new ChoseModelButton("关卡模式"), getWidth()/2, 300);
        addObject(new ChoseModelButton("游戏介绍"), getWidth()/2, 400);
    }
}
